In ArF liquid immersion lithography and extreme ultraviolet (EUV) lithography, processing dimensions of resist line widths have been required to be finer. In formations of such fine resist patterns, as the contact area between a resist pattern and a base substrate becomes smaller, the aspect ratio of the resist pattern (the height of the resist pattern/the line width of the resist pattern) becomes larger, which may facilitate collapse of the resist pattern. Therefore, a resist underlayer film (anti-reflective coating) that is in contact with a resist has been required to be highly adhesive to the resist so that collapse of the resist pattern is avoided.
It has been disclosed that, in achieving high adhesiveness of a resist under layer film to a resist, employing a lactone structure as a structural component of a resist underlayer film-forming composition improves adhesiveness of the resist underlayer film to a resist pattern to be obtained (Patent Document 1). In other words, by using a structure having a polar moiety such as a lactone structure as a structural component of a resist underlayer film-forming composition, adhesiveness to a resist pattern is expected to be improved, and collapse of a resist pattern is expected to be prevented even in a fine resist pattern.
However, in a lithography process requiring formation of finer resist patterns, such as ArF liquid immersion lithography and extreme ultraviolet (EUV) lithography, a lactone structure contained in a resist underlayer film-forming composition as a structural component does not sufficiently prevent collapse of a resist pattern.